From the earliest days, when Tesla first worked on wireless communication and power transfer, the reliability of a wireless connection has been a source of concern. On the communications side, years of incremental improvement yielded remarkable systems for data transfer (e.g., WIFI) and communication (e.g., cellular phones) but the connections have never been foolproof. As for wireless power transfers, some progress has been made, however, wireless energy transfer has not been widely adopted because of reliability and worries about safety. If wireless energy transfer was safer and more dependable, it would likely be widely accepted. For example, it could be used to power the numerous, battery-dependent, portable devices that consumers have in their home (smart phones, vacuum cleaners, etc.)
If wireless energy transfer were more robust, it could be also be used to power implanted medical devices. Wireless energy transfer to “life-critical” medical devices, such as Ventricular Assist Devices (VAD) would greatly improve the quality of life for patients requiring such devices. Patients having a VAD must constantly wear an external battery pack wired to the device. In addition to the inconvenience of wearing the pack, the wire connecting the battery and the device must be constantly cleaned and monitored to avoid infection. Nonetheless, despite the inconvenience, the use of wireless power for implantable devices—or even wireless communication for such devices—is restricted or avoided in most cases.
One attempt to implement wireless energy transfer for such devices is Transcutaneous Energy Transfer (TET), developed nearly a decade ago. TET uses closely spaced inductive coils, one implanted, and one outside the body, to transfer energy to an implanted rechargeable battery or device. However, just as in the days of Tesla, the technology suffers from concerns about the safety and reliability of the connections used to provide power and communication At the end of the day, a wired connections is far more likely to work than a wireless connection. For this reason, TET, or other implant power schemes, have not been widely adopted.
Some known wireless power transfer approaches are described in U.S. Pat. Nos. 6,772,011, 7,741,734, 7,613,497, 7,825,776, and 7,956,725 and in U.S. Patent Application Publication Nos. 2007-0132587, 2007-0182578, 2008-0041930, 2008-0238680, 2009-0243813, 2010-0045114, 2010-0052811, 2010-0081379, and 2010-0187913.